Foam type fire extinguisher



Oct. 31, 1950 c. H. LINDSAY FOAM TYPE FIRE EXTINGUISHER Filed Aug. 2,1945 fill/IIIIII/IIIII/IIII/III/III a I i Patented Oct. 31, 1950 UNITEDSTATES PATENT OFFICE FOAM TYPE FIRE EXTINGUISfiER Charles H. Lindsay,Elmira, N. Y., assignor to American-La France-Foamite Corporation,Elmira, N. Y., acorporation of New York Application August 2, 1945,Serial No. 608,434 I sfolaims. (cuss-2d) The invention is afoam-typefire extinguisher, more particularly of the kind and sizeusually mounted on wheels so as to be readily taken to the fire, andadapted to be inverted for action, but without limitation to anyparticular type. The object is to improve the foam-producing efticiencyof such apparatus which object is accomplished by a new organization ofthe internal solution compartments according to the principleillustrated in the accompanying drawing wherein Fig. l is a sideelevation of a so-called 40 gallon engine showing the invention applied;Fig. 2 an axial section in larger scale illustrating the extinguishercompartments and the preferred arrangement thereof, and

I Fig. 3 is a section on line III-III of Fig. 2.

The extinguisher shown in these figures comprises the usual mainreceptacle I, mounted on wheels 2 in the usual or any suitable way, sothat it can be tipped from its normal erect position, indicated indotted lines, to its working position indicated by full lines. Itcarries the usual hose rack 3, customary for these engines, has ahandlebar 4 and a foot 5, .by which it rests on the floor when in tippedposition.

The main receptacle l is for holding the usual basic foam-makingsolution which is compounded of sodium bicarbonate in water with anadded foam stabilizer according to standard formula. The companion acidsolution, compounded of aluminum sulfate and water, also according tostandard formula, is held in an inner receptacle 6, which in the presentcase is concentrically mounted in the main receptacle and so as to beremovable from it through the neck structure 1 of the main receptacle,after the screw-cap or cover 8 on the latter has been removed, thisbeing conventional arrangement. main receptacle around the innerreceptacle constitutes the basic solution compartment.

The inner receptacle is a cylindrical tube provided with a flange or rim9 at its top, whereby it is seated and held in place by the cover, andit contains or is provided with an outlet member In built into the tubeand adapted to be closed by a stopple II mounted on the end of ascrewshaft I2 having an external operating crank [3.

This stopple is for closing the outlet I to prevent escape of acidsolution while the extinguisher is being trundled to the fire,regardless of the attitude of the main receptacle at the time. The endof the tube 6, between the'outlet member I0 and the cover 8 constitutesthe mixing chamber or reaction space. It is fenestrated The space in the2 with four openings as indicated at I4 so as to admit the basicsolution into it.

The structure includes also a second outlet member I5 fixed to or builtinto tube 6 somewhat below or back of the valved outlet 10. Both ofthese outlet members may be castings or they may be constituted of asingle casting if desired. The second member 15 forms with the body oftube 6 a solution compartment which holds the bulk of theacid solution.The solution in this compartment flows through outlet [5 more or lessdirectly into the mixing chamber, when the apparatus is tipped and thestopple open, and the size of the outlet is especially calibrated sothat the flow through it will match therate of entry of the basicsolution into the mixing space through the open windows I4 and so as toproduce a constant and substantially stoichiometric combination of thetwo flows. It is referred toon this account as a metered outlet.

The annular space [6 between the two outlet members [0 and 15 forms anextra or third solution compartment, in this case coaxial with theothers. It is designed to contain a relatively small and predeterminedamount of the same acid solution as is contained ,in the main acidcompartment. It is important that it opens directly into the mixingchamber and through an adequately large outlet orifice so that it willinstantly supplement the flow of acid solution from the main acidcompartment when the latter flow begins, thus establishing a double flowof acid solution into the mixing chamber at the start of the operation.This flow continues only until the limited quantity of solution incompartment l6 has passed out. p

When the extinguisher is tipped for action, the mixing space is filled,Or fills, with basic solution via windows [4, before the arrival of anyacid solution. The efiect of the initial double flow of acid solution,into this body of basic solution, is to produce a substantially completeneutralization of the whole of such body, instantly making foam whichpasses out under its own expansion through the foam outlet presentlydescribed. Except for the amount of acid from the third compartment, themixing chamber would not receive enough acid, from outlet IE, to make acomplete reaction with the chamber contents and the acid charge placedin compartment I6 is predetermined with this object in view.

As soon as this initial action has taken place the remainders of the tworeagent solutions flow into the mixing space, the basic through thewindows I 4 and the acid through the metered outlet l5 and at therelative rates above referred to which produce a constantly neutral orin any event a desired quality of foam in the mixing space and until thetwo solutions are (simultaneously) exhausted.

The practical eifect of thus initially and instantly neutralizing thebasic contents of the mixing space is to eliminate the slug of solid,unreacted basic solution which otherwise would issue from the hosenozzle before the appearance of any foam, and it is due, in part atleast, to this saving that this extinguisher produces some 50% more foamfrom given quantities of solutions than has been derivable from thisclass of apparatus as heretofore designed.

The foam outlet from the mixing space is 10 cated on the main receptacleclose to the neck structure thereof and partially surrounds the tube 6at the mixing space. It comprises a box 19 with an arcuate perforatedwall 20, to serve as a screen located close to the tube 6 and concentrictherewith and so as to overlap or register with at least one of thewindow openings l4 therein. This box is held in position on the mainreceptacle by means of the hollow and perforated shank 2| of theelbow-fitting 22 to which the hose is attached. Foam made in the mixingspace thus passes directly therefrom into the box and through the elbowto the hose. With this arrangement the foam enters the hose practicallywhile it is being formed; also the screen 20 is exposed to plain viewfor inspection or cleaning when the inner receptacle has been removed.

The starting compartment 16 ordinarily receives its portion of the acidsolution at the time of charging the extinguisher. For convenience inthis connection, the outlet casting I5 is perforated at I! so that whenthe main acid receptacle is properly filled, that is to say, up to thelevel mark I8 therein, a proper amount of the solution flows through thehole and is thereafter held in the starting compartment; and even if theliquid level should be lower than the filling mark, such flow will inany event take place when the extinguisher is tipped for action beforethe stopple is opened, thus in any case charging the startingcompartment with the proper quantity of the acid solution for theinitial double flow into the mixing space.

It will be apparent that the principle of action above described isquite independent of the physical structure whereby the compartments areformed. Their concentric arrangement as illustrated is preferred becauseof its simplicity and servicing convenience.

Also it will be apparent that so long as the supplemental charge in thethird compartment is suflicient to cause such complete reaction it isnot important whether flow from that compartment thereupon ceasesabruptly or continues at a reduced rate so long as the relativeproportions of acid and basic entering the mixing chamber at the startof the operation are such as to produce a more or less stoichiometriccombination of the reagents and the continuing flows also are in suchconstant proportion.

I claim:

1. A foam-type fire extinguisher comprising a basic solutioncompartment, a mixing chamber in open communication therewith, and afoamoutlet leading from the mixing chamber, in combination with two'acid solution compartments, both having direct access to the mixingchamber, one of said acid solution compartments being of a capacity tocontain a supply of acidsolution adequate to react withthe basicsolution through:- out the normal solution mixing period, and the otherof said acid solution compartments being ofa capacity to contain alimited quantity of acid solution, to react with the basic solutioninitially in the mixing chamber.

2. The combination of claim ,1 in which said two acid solutioncompartments have communi: cation with each other whereby the chargingof, one with solution suffices to charge the other. i

3. The combination of claimv 1 in which said two compartments have asingle externally operated stopple for excluding the acid solution fromthe mixing chamber.

4. The combination of claim 1 in which said two compartments are coaxialwith each other and with the basic compartment.

. 5. The combination of claim 1 in which said two acid compartments andthe mixing chamber are all comprehended in a tubular structure removablyhoused in the compartment holding the basic solution.

CHARLES H. LINDSAY.

I REFERENCES CITED Thefollowing references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 58,627 Doughty Oct. 11, I875662,786 Harris' Nov. 27, 1900 858,188 Laurent June 25, 1907

